New study says yes – and here are five reasons why that could be (plus smartphones, of course)
Since the early 1900s, human intelligence has experienced an increase of about three to five points every 10 years due to factors such as improved nutrition, broader access to education, and test-taking familiarity. This generational rise in intelligence is well-established and referred to as the "Flynn Effect." While this may cause managers to sigh, raise their eyebrows as they think of their new staff and say “really?” recent studies say this may no longer be true.
Academic reports from parts of Europe and the US have begun to discover a stagnation in intelligence scores, and even a reversal of the effect. For instance, a recent US study observed lower vocabulary scores in more recent cohorts. Alarmingly, US college graduates in the 2010s had lower vocabulary scores than those in the 1970s.
To thoroughly investigate the Flynn Effect in recent times, three psychologists, two from Northwestern University and the third from the University of Oregon, carried out a pre-registered analysis of nearly 400,000 American adults from 2006 to 2018. The results showed that trends that had already been seen by European researchers were also occurring on American shores.
The researchers gathered cross-sectional data through the Synthetic Aperture Personality Assessment Project, which was advertised online as a personality test. They measured several domains of cognitive ability, including matrix reasoning (non-verbal reasoning), letter and number series (computational-mathematical reasoning), verbal reasoning, and 3D rotation (visuospatial skills). You can try the test yourself here.
Results indicated a reversal of the Flynn Effect for composite scores of cognitive ability, matrix reasoning, and letter and number series when participants were grouped by age, education, and gender. In other words, there was a downward trend in these domains of cognitive ability over generations. Yet, performance on 3D rotations increased over time.
The greatest differences were within groups of 18- to 22-year-olds as well as those without a college degree. To explain their results, the researchers offered five main explanations:
The researchers caution that cognitive ability scores might not accurately represent intelligence and note several limitations of the study, including self-selection of participants and potential motivation issues.
A report in Psychology Today also added a sixth potential cause – smartphones. During the period that the study covered (2006-2018) phone ownership grew from 3% to 81% - and people completing the study later may have done so on a smaller screen in distracting surroundings.
In support of the theory, a recent University of Chicago study indicates that the mere presence of a smartphone may actually deplete available resources – for spending on tests like these.
The Flynn effect, attributed to James R. Flynn from the University of Otago in NZ and initially introduced by Richard Herrnstein and Charles Murray in their 1994 book, "The Bell Curve," posits that human intelligence escalates with each new generation, resulting in a rise in average IQ scores.
Subsequent studies have supported this notion, revealing a consistent upward trend in IQ test scores for successive generations, with an increase of 3 to 5 points between 1932 and 2000. That effect, however, could be reversing.
Well, maybe – surgically removing a young employee from their smartphone may be an impossibility, but a study from the University of Pennsylvania, published in the Nature journal Scientific Reports, reveals that children who consume fish at least once a week experience improved sleep and have an average IQ score 4 points higher compared to their peers who eat fish less often or not at all.
